The present invention relates generally to fluorescent lamp light level control apparatus and systems, and more specifically to a controller apparatus for monitoring power input to fluorescent lamps via a user manipulated wall switch and a dimming ballast, and based upon a predetermined characteristic of OFF/ON cycles of the switch during a predetermined period, causing a corresponding adjustment of the control input to the ballast thus setting the light level to be output by the fluorescent lamps.
Personal light control dimmers allow users of the light sources to select a particular level of lighting for the environment in which they reside or work. The use of dimmers with incandescent lighting fixtures is well known. However, no such means has heretofore been popular for dimming fluorescent lighting fixtures although such sources are commonly used in both residential and work environments because they provide a more economical source of illumination.
Historically, fluorescent sources of illumination did not usually allow adjustment of intensity other than by selecting the number of available fixtures to be powered ON. Another approach has been to modify the AC power sine wave seen by a dimming ballast using a special phase control wall switch. This technique can distort the power to other devices connected to the switch and even effect negatively the utility transformer providing the power. More recently however, dimming ballasts have been made available which allow adjustment of the power applied to fluorescent lamps as a way to control the illumination. But the use of such dimming ballast has generally been limited to expensive control systems. There is thus a need for an economical, non power distorting apparatus or facility for allowing illumination control of fluorescent fixtures.
Among the various reasons why one would desire to have personal dimming control of overhead fluorescent lights include the desire to adjust the effects ambient lighting have on the use of computers, to compensate for incoming daylight or the lack thereof, to facilitate and enhance the ability to read printed text, and the creation of a suitable atmosphere for work.
Some people report eye strain and related symptoms due to too much, uncontrolled or excessively bright light. Others are concerned with the saving of energy, and still others believe that productivity improves when one has a choice as to how much light is actually wanted or needed. With respect to the saving of energy, having the ability to appropriately adjust lighting level can enable a typical office with two fluorescent fixtures to save up to 360 kilowatt hours of electrical power per year for a total dollar saving of approximately $50 per year while contributing to a cleaner environment.
Dimming fluorescent lights is different from dimming incandescent lights and requires two components and requires a dimming ballast in the overhead fixtures and a device with which to control the ballast so that it causes the lamps to generate a desired light level. Although dimming ballasts have been available for some time and the cost thereof is being significantly reduced every year, the control problem has been the principal stumbling block in the enablement of this facility in the home and office.
The lighting industry has in the recent past been providing elaborate solutions featuring daylight sensors, automated control scenarios, standardized control wiring and message protocols, these solutions, when seen from an installation and maintenance point of view, rival the intricacies of the PC networks used in most offices today. So even though available, such solutions prove to be quite costly and usually must be applied to a whole office suite to justify the architectural design expense. In addition, they require the installation of additional wiring infrastructure which normally disrupts the work place during the installation and has a high likelihood of causing a significant maintenance concern following installation.
The sophistication and complexity of available systems for the workplace may also require significant education of each employee as to how to properly use the system. Due to such cost and complexity issues, the likely addition of the enhanced lighting systems in new buildings is less than 1%, and is virtually 0% in existing or older buildings.
Present day systems for dimming or otherwise adjusting ambient light levels may certainly be achieved by lighting designers and architects, but dealing with the issues mentioned above may require a full fledged project resulting in significant investment in money, time and employee training on the part of the user.
Daylighting is one example of complexity wherein roof top or window based sensors are installed which measure outside light intensity and communicate information to an installed control system which, in turn, automatically adjusts the office lighting to a predetermined specified level to save or consume energy.
Building occupancy sensors are another popular input to the lighting control system which requires commissioning rules to be established. A central computer or each employee's personal computer may be used to control a lighting zone. This requires installation and configuration of a PC resident application on each employee PC. These lighting browsers are yet another complication, and as the seating arrangements for employees change, the applications have to be reconfigured.
These elaborate solutions and the costly and cumbersome sheetrock based changes to the walls of an existing structure to facilitate rewiring significantly increase the time and cost required for installation. This issue has restricted the above mentioned lighting control solutions, for the most part, to new building construction. While a professional design or the redesign of a building's lighting control system is the top end choice, the total cost of incorporating such systems is prohibitive for most companies.
It is therefore an objective of the present invention to provide a new solution to the above mentioned problems which eliminates the excessive cost, complexity and maintenance issues while at the same time providing the user with most if not all of the benefits.